1. Field of the Invention
The present invention relates to light-emitting diode displays and their forming methods.
2. Description of the Prior Art
Conventional full-color light-emitting diode (LED) displays employ red, green, and blue light-emitting diodes functioning as red, green, and blue light-emitting sub-pixels, respectively, and a color image is displayed according to the combination of emissions of these three types of sub-pixels.
The development of full-color light-emitting diode displays has many challenges to be overcome. For example, a challenge is related to the complicated and costly manufacturing process. The light-emitting diodes are typically grown on separate substrates, and they need to be transferred to a display substrate. The transfer is a difficult process due to the vast number of light-emitting diodes. For instance, the number of sub-pixels or the number of the light-emitting diodes of a 40-inch diagonal full HD (high definition) full-color display equals 1920×1080×3. Accordingly, there are 6,220,800 light-emitting diodes needed to be transferred and many of them may fail during the transfer.
In addition, because currently it is difficult to produce InGaN-based or AlGaInP-based light-emitting diodes on a substrate with a diameter more than 2 or 3 inches, red, green, and blue light-emitting diodes are usually formed in two or three individual substrates. A desired number of red, green, and blue LED diodes are then transferred and mounted to a single package to form a surface-mounted device (SMD), which is then mounted on a printed-circuit board.
Further, for driving the pixels, wire-bonding steps are usually needed to electrically connect the light-emitting diodes with the printed-circuit board or the display substrate.
Furthermore, the emitting efficiency, brightness, and other properties of LED displays are based on a hybrid approach or typically unsatisfactory.
Therefore, it would be advantageous to provide novel LED displays with improved configuration and manufacturing method as well as better performance.